Process for improving the bulk and resiliency of yarns

ABSTRACT

Yarn in skein form is introduced into a tumbler and subjected to the action of steam to increase the bulk of the yarn and render the bulk more uniform from end to end, and at the end of the steaming cycle valves are closed and exhaust fans are activated to remove steam from the chamber. The yarn is then subjected to air currents and dry heat to dry and further develop bulk in the yarn, after which the yarn is preferably subjected to further steam and heat setting steps.

United States Patent Lunsford et al.

[4 Oct. 24, 1972 PROCESS FOR IMPROVING THE BULK AND RESILIENCY 0F YARNS lnventors: Leslie E. Lunsford, Chattanooga, Tenn.; Clyde A. Simmons, Calhoun; William L. Evans, Dalton, both 0 Ga.

Assignee:

Filed: July 8, 1970 Appl. No.: 53,108

us. Cl. ..34/16, 34/23, 34/37.

Int Cl ..F26b 5/04 Field of Search ..34/12, 15, 16, 23, 37, 67;

' 8/1493; 28/721; 68/5 R, 5 A, 5 C

References Cited UNITED STATES PATENTS 6/ 1938 Wolfenderl ..8/ 149.3 X

fE'LF-CLOSING LOUVIQES STEAM HEAT/N6 COIL 5 Texture-Tex, Incorporated, Dalton,

3,576,661 4/1971 Dekockkocr ..34/37 3,528,180 9/1970 Karrer et al ..34/12 X 2,397,091 3/1946 Davis ..34/37 2,739,392 .3/1956 Thies ..34/37 X 2,364,467 12/ 1 944 Nickerson ..34/68 X Primary Examiner-Carroll B. Dority, Jr. Attorney-John X. Phillips [57] ABSTRACT Yarn in skein form is introdu'ced into a tumbler and subjected to the action of steam to increase the bulk of the yarn and render the bulk more uniform from end to end, and at the end of the steamingcycle valves are closed and exhaust fans are activated to remove steam from the chamber. The yarn is then subjected to air currents and dry heat to dry and further develop .bulk in the yarn, after which the yarn is preferably subjected to further steam and heat setting steps.

4 Claims, 4 Drawing Figures KOTAE Y TUMBLEE cv L INDEE.

3a STEAM PIPES a s n4 PATENTEDHBI 24 I972 P255502)? GAUGE L/ VESTEAM LINE 96 SHEET 2 BF 2 AUTOCLAVE I 82 EXHAl/5T VA L V5 -5H5KET 7 I CONVEYOR INVENTORS Les/A5 E A an sfo rd yde A. 5/07/77 0/7 5 William L. Evans ATTORNEY PROCESS FOR IMPROVING THE BULK AND RESILIENCY OF YARNS BACKGROUND OF THE INVENTION The invention relates particularly to a process for improving the bulk and uniformity of the bulk and increasing and rendering more permanent the bulk increase and resiliency of the yarn. In accordance with present practice, the yarn is subjected to the action of steam in a cylinder type tumbler, and at the end of a predetermined period of steaming, the tumbler is opened and the yarn removed. This constitutes the entire process commonly performed on yarn, particularly yarns made from man-made fibers, and has been considered relatively satisfactory even though yarn setters receive occasional complaints from tufters regarding the non-uniform yarn bulk and other related problems such as lack of resiliency and permanence of resiliency.

SUMMARY OF THE INVENTION described. Following the exhausting of steam and the admission of heated air to thetumbling apparatus, the yarn is removed from such apparatus and the fully developed bulk is highly advantageous in tufting rugs since the loftier yam tends to hold better in the carpet backing and allows the carpet to be made up with a much more uniform tufted length. The additional steps referred to, however, are much preferred because of the permanency of the increased and uniform bulk and the resiliency of the yarn.

In the next step in the process an apparatus is used which is in the nature of an autoclave and is referred to as such herein. The yarn treated as described above is placed in the autoclave and vacuum pumps are activated to reduce pressure in the autoclave to approximately 26 inches of mercury, which results in taking out what little residual moisture may remain in the yarn. The vacuum pump is then shut off and exhaust valves are opened, whereupon saturated steam is introduced into the autoclave to raise the temperature to i from 210 to 300 F. at substantial pressure. Depending of a tumbling apparatus similar to a laundry tumbler. I

Steam is introduced into the casing of the apparatus as the tumbler rotates to tumble the skeins of yarn while subjecting them to the action of steam. At the end of the preferred steaming cycle, the length of which depends upon the particular type of fibers being treated, the supply of steam is cut off and an exhaust fan exhausts the steam from the tumbler casing. This removal of the steam by the exhaust means greatly increases the quality of the fiber over conventional processes in which the steam is not thus exhausted.

It will be understood that the fibers are subjected to the action of a twister creel from which the yarn is taken up on a fiber twister spool. Two or more ends of the twisted yarn may be plied together to utilize the yarn in accordance with the ideas of the designer of the rug in which the yarn is to be used. The foregoing steps of the process, namely, the steam-treating of the yarn and the exhaustion of the steam from the tumbler, may be practiced on any type of twisted yarns as described and the bulk of the yarn will be increased materially over the bulk provided by the present process and the resiliency of the yarn will be greatly increased, although not with the degree of permanency desired. In most cases the perforated tumbler will be rotated preferably about revolutions per minute during the introduction of the steam, and the steaming operation is usually carried out for from three to six minutes.

During the exhausting of the steam from the tumbling apparatus, dry air is admitted to the latter so that the exhaust operation not only takes out all of the steam but effects substantial drying of the yarn with the highly advantageous results referred to. During the exhaustion of the steam and admission of air to the tumbling apparatus, the air being admitted is subjected to the action of heaters to insure that the exhausting of the steam will be followed by substantial drying of the yarn. The operation of exhausting the steam and admitting heated air to the tumbling apparatus is usually carried out for 5 or 6 minutes.

While the foregoing steps provide substantially improved bulk and resiliency in the yarn, further steps are preferably carried out to provide results far superior to the conventional process for the process steps just upon the type of yarn being treated, a 30 second to 10 minute cycle is used to maintain the desired time and temperature of the steaming cycle in the autoclave. Upon the completion of such cycle, the admission of steam is cut off and an exhaust valve is opened to reduce pressure in the autoclave to that of the atmosphere. The steaming and exhausting steps in the autoclave may be carried out from one to as many as 24 times if desired.

After the completion of the steaming and exhausting cycles in the autoclave, the yarn is removed and is ready for the final drying and heating. To accomplish this step, the yarn, still in skein form, is moved through a hot air drier to remove any moisture remaining after the autoclave treatment. From the drier, the yarn is wound onto a cone or similar package ready to be shipped to the customer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of a suitable tumbling apparatus with the exhaust means broken away; FIG. 2 is a section on line2-2 of FIG. 1;

FIG. 3 is a sectional view through an autoclave illustrating diagrammatically the associated pressure gauge, vacuum pump, vacuum gauge, live steam line and exhaust valve, and

FIG. 4 is a diagrammatic face view of the final drier.

DESCRIPTION OF TI-IE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, the numeral 10 designates a tumbling apparatus as a whole comprising an outer imperforate stationary shell 12 having a depending longitudinal extension 14 resting on the floor 16. A similar extension 18 is provided at the top of the outer casing and this extension is open throughout its length at the top thereof as at 20. This opening is normally closed by self-closing louvers 22 which may be of any conventional type. These louvers will be closed when steam is admitted to the casing as described below and will automatically open when air is exhausted from the casing. Extending longitudinally of the extension 18 is a heating means preferably in the form of steam pipes 24 supplied with steam by pipes 26 and from which steam is withdrawn through pipes 28.

In the lower extension 14 is arranged preferably a pair of steam pipes 30 extending longitudinally of the apparatus and each being provided with a line of perforations 32 through which steam can escape into the casing 12. These pipes are closed at their ends 34 and steam is introduced into the opposite ends of the pipes 30 through supply pipes 36. The casing is provided in the front thereof with an opening 38 for the introduction and removal of the yarn and this opening is normally closed by doors 40 sliding in guides 42.

Within the casing 12 is arranged a rotating cylinder 44 provided with a substantial number of perforations 46 extending circumferentially and longitudinally of the cylinder 44. This cylinder is supported on a shaft 48 extending through the ends of the casing 12 and supported in bearings 50. One end 52 of the shaft is extended (FIG. 1) for connection with any suitable source of power for rotating the shaft and the cylinder The tumbling cylinder is provided in one side with an opening 54 (FIG. 2) normally covered by sliding doors 56 operable in guides 58. The doors 56 are also preferably perforated as at 60, and accordingly steam from the pipes 30 is adapted to flow relatively freely into the tumbling cylinder 44 to treat the yarn therein.

Preferably centrally of the length thereof, the extension 14 is provided with an opening 62 communicating with an exhaust pipe 64. This exhaust pipe extends laterally of the tumbling apparatus then longitudinally thereof as at 66 and then upwardly as at 68, preferably beyond the end of the tumbling apparatus. The pipe 68 is connected to the intake of a centrifugal exhaust fan 70 having conventional outlet 72. The exhaust fan is supported on a suitable cradle 74.

In the practice of the process, the twisted yarn in skein form is introduced into the cylinder 44 after opening the doors 40 and 56, whereupon these doors are closed, rotation of the cylinder 44 is started and steam is supplied to the pipes 30 to subject the skeins of yarn to the action of the steam as the skeins are tumbled in the cylinder 44. At this time, the louvers 22 will be closed. At the end of the steaming cycle, the admission of steam to the pipes 36 is cut off, steam is admitted to the pipes 26 to flow through the heating pipes 24, and the exhaust fan 70 is started in operation. All of these steps may be carried out simultaneously. With the cylinder 44 continuing to rotate, the exhausting of the steam by the exhaust fan will be accompanied by the flowing into the apparatus of air pressure which will open the louvers 22. This air flows downwardly into the casing 12 over the heating coils 24 and into the tumbling cylinder 44. Thus all of the steam will be exhausted from the apparatus and the yarn will be subjected to the action of heated air to dry it.

The tumbling cylinder 44 will be rotated preferably at approximately 25 revolutions per minute. The skeins will be subjected to the steam action preferably from 3 to 6 minutes, and the heated air is admitted usually for from 5 to 6 minutes to effect the substantial drying of the yarn. The tumbler cylinder 44 is then stopped with theopening 54 registering with the opening 38, whereupon the skeins of yarn are removed from the tumbling apparatus and the exhausting of steam and the heating of the air by the coils 24 will greatly improve the degree and uniformity of the bulk of the yarn. This yarn will be of much better quality than yarn taken directly from the tumbling apparatus after a steaming operation only.

The yarn removed from the tumbling apparatus is placed in a basket 76 (FIG. 3) placed on supports 78 in a casing 80 constituting what is substantially a conventional autoclave. This autoclave has a sealed cover 82 which is clamped in position after the placing of the basket 76, as shown in FIG. 3. This basket should be so constructed as to permit the free flow of steam through the yarn therein, some skeins of which, indicated by the numeral 80, are shown in FIG. 3. In the present instance, the basket is shown as being formed of sheet metal having perforations 82 in the sides, ends and bottom of the basket.

After the basket is placed in position, air is exhausted from the autoclave by operation of a vacuum pump 84 connected to the autoclave by an exhaust line 86 in which is arranged a vacuum gauge 88. The exhausting of air from the autoclave is carried out to a degree of vacuum approximating 26 inches of mercury. When such degree of vacuum has been attained in the autoclave, the vacuum time cycle is completed and the vacuum pump 84 is shut off.

The autoclave is provided with an exhaust pipe 90 having a control valve 92 which, of course, is closed during the exhaust operation carried on by the pump 84, and upon completion of the vacuum cycle, the valve 92 remains closed. With the high degree of vacuum existing in the autoclave, a valve 94 in a steam line 96 is opened to permit the flow of live steam into the autoclave to raise the temperature therein to from 210 to 300 F. The admission of steam, of course, raises the pressure in the autoclave and results in the thorough saturation of the yarn fibers by steam. Any desired superatmospheric pressure may be provided by the live steam and such pressure will be indicated by a gauge 98. i

r The steaming of the yarn in the autoclave may be carried out, after superatmospheric pressure is reached, for a 30 second to a 10 minute cycle, depending upon the material being treated. When this cycle is completed, the valve 94 is closed and the exhaust valve 92 is opened to reduce pressure in the autoclave to that of the atmosphere. For further advantageous results if necessary, the exhaust valve 92 may be closed and the steam valve opened and the steaming of the yarn and exhausting of the steam from the autoclave may be carried out again. Such complete cycle may be repeated up to 24 times. Upon completion of these cycles, the yarn is ready for the final drying operation.

With the exhaust valve 92 opened, the cover 82 of the autoclave is opened or removed and the basket 76 containing the treated skeins of yarn is placed on a conveyor 100 (FIG. 4) and moved thereby through a hot air drying tunnel 102. This tunnel is preferably from 30 to 40 feet long and it normally requires about 45 minutes for each basket to pass completely through the drier 102. This drier may be heated by any desired means to any desired temperature to completely remove all moisture from the yarn remaining therein after the steam treatment in the autoclave.

The practice of the process has been found to provide, particularly in man-made fibers, a degree of bulk never before attained and this bulk will be uniform from end to end of the yarn and the yarn will possess a high degree of permanency in its bulk and resiliency. As previously indicated, much better than conventional results are obtained through the initial steps of steaming the yarn in the tumbling apparatus and then exhausting the steam and simultaneously introducing heated air into the yarn to dry it. This is all accomplished by the apparatus shown in FIGS. 1 and 2. Each successive step further improves the quality as to degree of uniformity and resiliency of the bulk of the yarn. As a result, satisfactory coverage per square yard of carpet may be accomplished with fewer tufts which is a definite economic advantage. Moreover, the fully developed bulk in the yarn is highly advantageous for the rug tufters since the loftier yarn tends to hold better in the carpet backing and allows the carpet to be made up with much more uniform tuft length.

What is claimed is:

l. A process of increasing the bulk and permanence of elasticity of yarns which comprises subjecting a skein of yarn solely to the action of steam in a closed container for a period of time, thereafter exhausting the steam from the container and supplying heated air to the interior thereof, and tumbling the yarn in the container during the foregoing steps.

2. The process defined in claim 1 together with the following steps of subjecting the yarn to relatively high vacuum and then increasing the pressure in the yarn to atmospheric pressure, and thereafter subjecting the yarn to superatmospheric pressure and then releasing such pressure.

3. The process defined in claim 1 wherein the admission of steam to the container is accompanied by a rise in temperature in the latter to between 210 and 300 F, after which the yarn is removed from said container and placed in a sealed container and subjected successively to vacuum, atmospheric pressure and then superatmospheric pressure. 

1. A process of increasing the bulk and permanence of elasticity of yarns which comprises subjecting a skein of yarn solely to the action of steam in a closed container for a period of time, thereafter exhausting the steam from the container and supplying heated air to the interior thereof, and tumbling the yarn in the container during the foregoing steps.
 2. The process defined in claim 1 together with the following steps of subjecting the yarn to relativEly high vacuum and then increasing the pressure in the yarn to atmospheric pressure, and thereafter subjecting the yarn to superatmospheric pressure and then releasing such pressure.
 3. The process defined in claim 1 wherein the admission of steam to the container is accompanied by a rise in temperature in the latter to between 210* and 300* F, after which the yarn is removed from said container and placed in a sealed container and subjected successively to vacuum, atmospheric pressure and then superatmospheric pressure.
 4. A process according to claim 3 wherein the superatmospheric pressure is released, the yarn is removed from the sealed container and subjected to a thorough heating action to dry the yarn. 